Efficacy and safety of pulmonary artery catheterization with combined transesophageal echocardiography and pressure waveform: A prospective observational study.

Objective: This study investigated whether pulmonary artery catheter placement method with combined transesophageal echocardiography and pressure waveform measurement improve the placement success rate within 5 min and reduce the incidence of arrhythmia during pulmonary artery catheter placement compared to conventional pulmonary artery catheter placement with pressure waveform measurement only. Methods: This single center prospective observational study included 129 patients scheduled for cardiac surgery. Patients were divided into two groups. In the conventional group, the pulmonary artery catheter was placed by monitoring the pressure waveform and the length of placement; in the combination group, not only were the pressure waveform and the length monitored but also the following transesophageal echocardiography images: "mid esophageal bicaval view," " mid esophageal modified bicaval view," a mirror image of "mid esophageal 4 chamber view," "mid esophageal right ventricular inflow-outflow view," and "mid esophageal ascending aortic short axis view." Results: A 1:1 propensity score matching was used to adjust for confounding factors. The success rates of pulmonary artery catheter placement within 5 min in the conventional and combination groups were 85.5 % vs. 97.8 % (p = 0.032) before matching, and 73.7 % vs. 100 % (p = 0.001) after matching. The incidences of arrhythmias in the conventional and combination groups were 28.9 % vs. 17.4 % (p = 0.20) before matching, and 28.9 % vs. 18.4 % (p = 0.42) after matching. Conclusion: Pulmonary artery catheter placement with transesophageal echocardiography had a significantly higher rate of successful placement within 5 min, but no significant differences were observed in the incidences of arrhythmias.

Delayed migration of a Sapien 3 Ultra Resilia following transcatheter aortic valve implantation after selection of a smaller-sized valve.

This report discusses a rare case of delayed migration of a Sapien 3 Ultra Resilia (S3UR) valve following transcatheter aortic valve implantation. An 81-year-old Japanese woman had a borderline aortic annular size of 20-23 mm according to the manufacturer's size chart. We chose to implant a smaller S3UR of 20 mm with an 80/20 depth ratio to allow for a second intervention, ensuring good hemodynamics and minimizing paravalvular leak. The patient initially had a favorable outcome despite an accidental 50/50 depth ratio during implantation. On postoperative day 3, the S3UR migrated into the left ventricular outflow tract. Emergency surgical aortic valve replacement was performed to retrieve the migrated valve. Use of the S3UR has led to a growing preference for smaller valve sizes. However, the risk of migration should be recognized. When an accidental 50/50 depth ratio implantation is encountered, post-dilation or second valve implantation should be performed immediately.

Relationship between Tryptase and Hypotension in Anaphylaxis during Anesthesia.

INTRODUCTION: Hypotension is a cardiovascular symptom that appears at the onset of anaphylaxis. It is considered an important factor as it affects the severity of anaphylaxis; however, its details remain to be elucidated. In this study, we investigated the characteristics of hypotension at the onset of anaphylaxis during anesthesia, along with the relationship between hypotension, tryptase and histamine. MATERIALS AND METHODS: The minimum systolic blood pressures of patients diagnosed with anaphylaxis using the clinical diagnostic criteria of the World Allergy Organization guidelines were extracted from electronic anesthesia records. We analyzed changes in tryptase and histamine that were measured after the onset of anaphylaxis. We analyzed the relationship of tryptase and histamine with the minimum systolic blood pressure and the severity of anaphylaxis. RESULTS: Of 55,996 patients, 25 were diagnosed with anaphylaxis during anesthesia (0.045%). Among these patients, the minimum systolic blood pressure was less than 90 mmHg. Furthermore, the minimum systolic blood pressure was inversely correlated with tryptase levels immediately to 1 hour, and 2 to 4 hours after the onset of anaphylaxis. The minimum systolic blood pressure was inversely correlated with the severity of anaphylaxis. The severity of anaphylaxis was positively correlated with tryptase levels immediately to 1 hour, and 2 to 4 hours after the onset of anaphylaxis. CONCLUSION: Hypotension tended to reflect the severity of anaphylaxis. Tryptase is an adjunct in the diagnosis of hypotension and may be a useful indicator of the severity of anaphylaxis. A larger-scale study is needed to validate these results.

Cusp overlap technique decreases paravalvular leakage in self-expandable transcatheter aortic valve replacement.

The cusp overlap technique allows greater visual separation between the basal annular plane and the conduction system and decreases the permanent pacemaker implantation rate. We assessed the impact of the cusp overlap technique on conduction disturbance and paravalvular leakage after transcatheter aortic valve replacement. A total of 97 patients underwent transfemoral transcatheter aortic valve replacement with self-expandable valves at our institution from November 2018 to January 2023. The mean age of the patients was 85 years, and 23% were male. The patients were divided into two groups: the cusp overlap technique group and the non-cusp overlap technique group. We compared the clinical results between the two groups. The 30-day permanent pacemaker implantation rate was similar between the two groups (cusp overlap technique: 6.3% vs. non-cusp overlap technique: 10.2%, p = 0.48). The rate of new-onset conduction disturbance was slightly lower in the cusp overlap than non-cusp overlap technique group (18.8% vs. 34.7%, respectively; p = 0.08). The implanted valve function was similar between the two groups, but the rate of trivial or less paravalvular leakage (PVL) was significantly higher in the cusp overlap technique group on echocardiography (69% vs. 45%, p = 0.02). On multidetector computed tomography, the implantation depth at the membranous septum was significantly shorter in the cusp overlap technique group (2.0 ± 2.3 vs. 2.9 ± 1.5 mm, p = 0.02). The degree of canting was slightly smaller in the cusp overlap technique group (1.0 ± 2.2 vs. 1.7 ± 1.9 mm, p = 0.07). The relative risk of PVL equal to or greater than mild was 1.76 times higher for valve implantation without the cusp overlap technique (adjusted odds ratio, 3.74; 95% confidence interval, 1.45-9.69; p < 0.01). Transcatheter aortic valve replacement using the cusp overlap technique is associated with an optimized implantation depth, leading to fewer conduction disturbances. Optimal deployment may also maximize the radial force of self-expanding valves to reduce paravalvular leakage.

Anesthetic management of a patient with methamphetamine-associated pulmonary arterial hypertension undergoing laparoscopic cholecystectomy.

BACKGROUND: Methamphetamine abuse is a serious public health concern and causes various life-threatening disorders including pulmonary arterial hypertension (PAH). Herein, we present the first case report describing the anesthetic management of a patient with methamphetamine-associated PAH (M-A PAH) undergoing laparoscopic cholecystectomy. CASE PRESENTATION: A 34-year-old female with M-A PAH suffered from deterioration of right ventricular (RV) heart failure due to recurrent cholecystitis and was scheduled for laparoscopic cholecystectomy. Preoperative assessment of PA pressure showed 82/32 (mean, 50) mmHg, and transthoracic echocardiology revealed a slight reduction of RV function. General anesthesia was induced and maintained by thiopental, remifentanil, sevoflurane, and rocuronium. PA pressure gradually increased after peritoneal insufflation; therefore, we administered dobutamine and nitroglycerin to decrease pulmonary vascular resistance (PVR). The patient emerged from anesthesia smoothly. CONCLUSIONS: Avoiding increased PVR by appropriate anesthesia and medical hemodynamic support is an important consideration for patients with M-A PAH.

The Involvement of Cx43 in JNK1/2-Mediated Endothelial Mechanotransduction and Human Plaque Progression.

Atherosclerotic lesions preferentially develop at bifurcations, characterized by non-uniform shear stress (SS). The aim of this study was to investigate SS-induced endothelial activation, focusing on stress-regulated mitogen-activated protein kinases (MAPK) and downstream signaling, and its relation to gap junction proteins, Connexins (Cxs). Human umbilical vein endothelial cells were exposed to flow ("mechanical stimulation") and stimulated with TNF-α ("inflammatory stimulation"). Phosphorylated levels of MAPKs (c-Jun N-terminal kinase (JNK1/2), extracellular signal-regulated kinase (ERK), and p38 kinase (p38K)) were quantified by flow cytometry, showing the activation of JNK1/2 and ERK. THP-1 cell adhesion under non-uniform SS was suppressed by the inhibition of JNK1/2, not of ERK. Immunofluorescence staining and quantitative real-time PCR demonstrated an induction of c-Jun and c-Fos and of Cx43 in endothelial cells by non-uniform SS, and the latter was abolished by JNK1/2 inhibition. Furthermore, plaque inflammation was analyzed in human carotid plaques (n = 40) using immunohistochemistry and quanti-gene RNA-assays, revealing elevated Cx43+ cell counts in vulnerable compared to stable plaques. Cx43+ cell burden in the plaque shoulder correlated with intraplaque neovascularization and lipid core size, while an inverse correlation was observed with fibrous cap thickness. Our results constitute the first report that JNK1/2 mediates Cx43 mechanoinduction in endothelial cells by atheroprone shear stress and that Cx43 is expressed in human carotid plaques. The correlation of Cx43+ cell counts with markers of plaque vulnerability implies its contribution to plaque progression.

Expression of the pacemaker channel HCN4 in excitatory interneurons in the dorsal horn of the murine spinal cord.

In the central nervous system, hyperpolarization-activated, cyclic nucleotide-gated (HCN1-4) channels have been implicated in neuronal excitability and synaptic transmission. It has been reported that HCN channels are expressed in the spinal cord, but knowledge about their physiological roles, as well as their distribution profiles, appear to be limited. We generated a transgenic mouse in which the expression of HCN4 can be reversibly knocked down using a genetic tetracycline-dependent switch and conducted genetically validated immunohistochemistry for HCN4. We found that the somata of HCN4-immunoreactive (IR) cells were largely restricted to the ventral part of the inner lamina II and lamina III. Many of these cells were either parvalbumin- or protein kinase Cγ (PKCγ)-IR. By using two different mouse strains in which reporters are expressed only in inhibitory neurons, we determined that the vast majority of HCN4-IR cells were excitatory neurons. Mechanical and thermal noxious stimulation did not induce c-Fos expression in HCN4-IR cells. PKCγ-neurons in this area are known to play a pivotal role in the polysynaptic pathway between tactile afferents and nociceptive projection cells that contributes to tactile allodynia. Therefore, pharmacological and/or genetic manipulations of HCN4-expressing neurons may provide a novel therapeutic strategy for the pain relief of tactile allodynia.

Massive obstetric hemorrhage during cesarean section in a patient after conception by frozen-thawed embryo transfer: a case report.

BACKGROUND: Placenta accreta is a major cause of massive obstetric hemorrhage during cesarean section. In recent years, pregnancy by in vitro fertilization-embryo transfer has been reported as a risk factor for placenta accreta. CASE PRESENTATION: A 36-year-old G1P0 woman with systemic lupus erythematosus became pregnant by frozen-thawed embryo transfer. Emergency cesarean section was performed under general anesthesia due to the diagnosis of non-reassuring fetal status. The placenta invaded the myometrium and completely covered the entire anterior uterine wall. Following birth, 3000 mL of blood loss required rapid fluid infusion and blood transfusion. Total hysterectomy was performed because the placenta could not be separated from the uterine wall. Histological examination revealed placenta accreta/increta. CONCLUSIONS: When performing cesarean section on patients who have undergone frozen-thawed embryo transfer, preoperative examinations to assess for placenta accreta should be performed, and the anesthetic management should include sufficient planning for massive obstetric hemorrhage.

Overexpression of the HCN2 channel increases the arrhythmogenicity induced by hypokalemia.

Hypokalemia, an abnormally low level of potassium (K+), is a electrolyte imbalance that commonly occurs in heart failure patients. Hypokalemia is well known to induce lethal ventricular arrhythmia. However, the effects of hypokalemia in failing hearts that have undergone electrophysiological remodeling, i.e., the reactivation of fetal-type ion channels, remain unexplored. We have examined the effect of hypokalemia in the myocytes of transgenic mice overexpressing the hyperpolarization-activated, cyclic nucleotide-sensitive (HCN) channel in the heart (HCN2-Tg mice). Perfusion with a mild hypokalemic solution containing 3 mM K+ induced ectopic ventricular automaticity in 55.0% of HCN2-Tg mouse myocytes. In the remaining HCN2-Tg mouse myocytes, the resting membrane potential (RMP) was more depolarized than that of wild-type myocytes subjected to the same treatment and could also be hyperpolarized by an HCN channel blocker. We conclude that in hypokalemia in our mice model, the HCN2 channel was constitutively activated at the hyperpolarized RMP, thereby destabilizing the electrophysiological activity of ventricular myocytes.

Clinical Concentrations of Local Anesthetics Bupivacaine and Lidocaine Differentially Inhibit Human Kir2.x Inward Rectifier K+ Channels.

BACKGROUND: Inward rectifier K channels of the Kir2.x subfamily are widely expressed in neuronal tissues, controlling neuronal excitability. Previous studies reported that local anesthetics (LAs) do not affect Kir2 channels. However, the effects have not been studied at large concentrations used in regional anesthesia. METHODS: This study used the patch-clamp technique to examine the effects of bupivacaine and lidocaine on Kir2.1, Kir2.2, and Kir2.3 channels expressed in human embryonic kidney 293 cells. RESULTS: When applied extracellularly in whole-cell recordings, both LAs inhibited Kir2.x currents in a voltage-independent manner. Inhibition with bupivacaine was slow and irreversible, whereas that with lidocaine was fast and reversible. Kir2.3 displayed a greater sensitivity to bupivacaine than Kir2.1 and Kir2.2 (50% inhibitory concentrations at approximately 5 minutes, 0.6 vs 8-10 mM), whereas their sensitivities to lidocaine were similar (50% inhibitory concentrations, 1.5-2.7 mM). Increases in the charged/neutral ratio of the LAs at an acidic extracellular pH attenuated their inhibitory effects, and a permanently charged lidocaine derivative QX-314 exhibited no effects when applied extracellularly. Inside-out experiments demonstrated that inhibition of Kir2.1 with cytoplasmic lidocaine and QX-314 was rapid and reversible, whereas that induced by bupivacaine was slow and irreversible. Furthermore, dose-inhibition relations for the charged form of bupivacaine and lidocaine obtained at different cytoplasmic pHs could be approximated by a single relation for each LA. CONCLUSIONS: The results indicate that both LAs at clinical concentrations equilibrated rapidly with the intracellular milieu, differentially inhibiting Kir2.x channel function from the cytoplasmic side.

Ectopic automaticity induced in ventricular myocytes by transgenic overexpression of HCN2.

Hyperpolarization-activated cyclic nucleotide-gated channels (HCNs) are expressed in the ventricles of fetal hearts but are normally down-regulated as development progresses. In the hypertrophied heart, however, these channels are re-expressed and generate a hyperpolarization-activated, nonselective cation current (Ih), which evidence suggests may increase susceptibility to arrhythmia. To test this hypothesis, we generated and analyzed transgenic mice overexpressing HCN2 specifically in their hearts (HCN2-Tg). Under physiological conditions, HCN2-Tg mice exhibited no discernible abnormalities. After the application of isoproterenol (ISO), however, ECG recordings from HCN2-Tg mice showed intermittent atrioventricular dissociation followed by idioventricular rhythm. Consistent with this observation, 0.3 µmol/L ISO-induced spontaneous action potentials (SAPs) in 76% of HCN2-Tg ventricular myocytes. In the remaining 24%, ISO significantly depolarized the resting membrane potential (RMP), and the late repolarization phase of evoked action potentials (APs) was significantly longer than in WT myocytes. Analysis of membrane currents revealed that these differences are attributable to the Ih tail current. These findings suggest HCN2 channel activity reduces the repolarization reserve of the ventricular action potential and increases ectopic automaticity under pathological conditions such as excessive ß-adrenergic stimulation.